fast twitch muscle fiber

hey guys how do you know if you have fast twitch fibers in your body. Especially in the legs. Lately ive been working on getting my deadlift numbers up. 255lbsx6 reps at a bodyweight of 164 pretty descent? It seems to be helping me explode in the air.

people who have fast twitching fibers usually are good at powerlifting, sprint, explosive type stuff, but the fast twitch tends to fatigue faster. if a person has more slow twitching fibers, they tend to be long distance runners, high endurance, etc. its also more fatigue resistant than the fast twitching fiber. the fibers are genetically pre-determined. most people are 50/50, but there are those who have more than the other.

just ask yourself, are you a high endurance athlete or a power athlete? endurance=slow fast=power.

hey guys how do you know if you have fast twitch fibers in your body. Especially in the legs. Lately ive been working on getting my deadlift numbers up. 255lbsx6 reps at a bodyweight of 164 pretty descent? It seems to be helping me explode in the air.

I do this twice a week and i have gained speed and conditioned my fast twitch muscles, as well as lost fat.

I don't really like your attitude.

I was waiting for OP to respond to my 2nd post about why he is concerned about FT muscle fibers and 'how many he has'.

Even if I do not feel like posting its still better to say when some1 is wrong than to say nothing at all.

HIIT is mainly used to burn fat and if your looking to 'gain' ft fibers it should not concern OP unless he wants to lose weight, and what you listed is a pretty odd HIIT.

As for OP decent relative strength is 1.5bw squat, good strength is 2xbw squat. You said you were looking to get your deadlift numbers up? Why deadlift and not mention squat? Chances are you will get more out of increasing your squat and 'focusing' on your squat.

More important than being worried about fast-twitch fibers is being worried about how fast you generate force+how much total force you put out in your sports movements, yes there is a connection between the two but the latter is more important to you. Basically your main focus should be getting your lifts up using high weight, low reps and accelerating through the lifts. If you have good strength numbers and poor sports performance(vj, acceleration, basic power output) than chances are your body is just taking to much time to output peak force. You should do some RFD exercises, the best being jump squats with 30-50% of your max squat, this will improve your force curve and move it to the left. Also improving rfd but with other and equally important benefits are plyometrics,most importantly they will also help your body learn to absorb and re-output force through the SSC.

If your lifting correctly, your fast-twitch fibers will increase in size. Thats not all you need to be concerned with.

If you do not currently have a program, there are very few sports specific programs that are actually good. But westside for skinny bastards is a good one.

If you train powerlifting style than your really not doing dmg to yourself(if your lifting bb style, stop), but you will need to go through a conversion/power/plyometric phase eventually to see great increases in sports performance.

You get your squat up and general leg strength up.
You use RFD exercises to get your force curve to shift to the left.
You use plyometrics for increase efficiency of the plyometric reflex, general mechanics, and greater force output.

If your lifting correctly, your fast-twitch fibers will increase in size. Thats not all you need to be concerned with.

forgot to mention this. you cannot gain more fast twitch muscles. what ever you have you have. with training you can increase the size of the fiber. you can also increase strength and the actin/myosins in the muscles.

hey guys how do you know if you have fast twitch fibers in your body. Especially in the legs. Lately ive been working on getting my deadlift numbers up. 255lbsx6 reps at a bodyweight of 164 pretty descent? It seems to be helping me explode in the air.

Like it was mentioned earlier we all have FT & ST muscle fibres throughout our bodies. The distribution of them are different in all muscle groups within the body. The percentage of FT vs ST is determined by your genetics (MOM & DAD). Most muscles contain both types.

And as far as splitting fibers or creating new ones. Your looking to make the fibers bigger not split or create new ones.

You reckon?
There is a debate and no one yet agrees on what improves a muscle better.
The increase in size of fibers OR the increase in the numbers of fibers.

AND before anyone says "it's proven that it's like this ----" there is no solid answer yet.

I would think that more fibers would be better because I see it like this...if you had a few thick ropes together...that would be weaker then hundreds of little ropes together. I see them like cables...cables are hundreds of little metal fibers together and they are really strong.

You reckon?
There is a debate and no one yet agrees on what improves a muscle better.
The increase in size of fibers OR the increase in the numbers of fibers.

AND before anyone says "it's proven that it's like this ----" there is no solid answer yet.

I would think that more fibers would be better because I see it like this...if you had a few thick ropes together...that would be weaker then hundreds of little ropes together. I see them like cables...cables are hundreds of little metal fibers together and they are really strong.

IDK...just my opinion.

Its the size of the muscle fibers that improves. If the number improves it is incredibly significant.

It is proven that any significant gains will be the size of the fibers not the number of fibers.

I agree Lucky. I hate to see statements posted so blindly without any type of evidence. For example, I would like to see some support for the following statements:

I got into this thread because other people needed to be corrected. Saying my statement is 'blind' is drastic and incorrect. I'm not going to post studys to backup everything. Its not like I said something like 'do plyos to test your fast twitch fibers' or 'do HIIT to help increase number of FT fibers' or 'I think muscle hyperplasia is more important than hypertrophy' or 'doing sub maximal plyometrics will build FT fibers'........ and im not sure what gymrat so i dont know how you would want him to back it up, i'd ask him to put it into english first, he did use the word 'create' though so I assume he is far off.........

I got into this thread because other people needed to be corrected. Saying my statement is 'blind' is drastic and incorrect. I'm not going to post studys to backup everything. Its not like I said something like 'do plyos to test your fast twitch fibers' or 'do HIIT to help increase number of FT fibers' or 'I think muscle hyperplasia is more important than hypertrophy' or 'doing sub maximal plyometrics will build FT fibers'........ and im not sure what gymrat so i dont know how you would want him to back it up, i'd ask him to put it into english first, he did use the word 'create' though so I assume he is far off.........

I just post what worked for me as an example, If no one likes it then move on and get over it.

2. What research I have seen is circumstantial at best, meaning there is no concrete proof that conversion occurs.

3. I have not done in-depth research on the topic, which is why I am interested in further evidence if it is available.

So, yes Sillz, I think your statement is out of line if you are basically just spouting it off from your head. I'm not saying your wrong. I'm saying the evidence is not clear , and if you have data to support your statement, please share so that we can all learn.

If I'm not mistaken, there are studies that have proven that type IIb fibers can actually turn into more of a type IIa fiber with both resistance training and aerobic training.

Here are excerpts from 2 relevant studies:

The conversion probably proceeds from type IIb to type IIa to type IIx then type I. In fact, evidence now indicates that the fast twitch contractile proteins (type IIa and probably also IIb) are constitutively expressed (expressed by default in the organism) and that it takes some kind of stimulus to express the type I contractile proteins. This is supported by the numerous studies on muscle adaptions to disuse. If muscles are not allowed to contract (eg, by severing the nerve or physically immobilizing the limb) the muscles begin to express the fast contractile proteins. The longer the immobilization, the more fast twitch the muscles become.

Dr. Giarnella is correct to the extent that it has been difficult to demonstrate a conversion of type I fibers to type II due to exercise training. The current theory proposes that type IIb fibers are converted to type IIa during strength training and type IIb are converted to IIa and type IIa to type I during endurance training programs. Years ago it was assumed that muscle fiber type was fairly stable and genetically determined. This has been disproven in recent years by literally hundreds of studies indicating that muscles posses an incredible degree of plasticity.

The objective of this research was to investigate the effects of beef extract on fat metabolism, muscle mass and muscle fiber types in rats. We also investigated the synergetic effect of endurance exercise. Twenty-four male rats weighing about 270 g were assigned to two diets containing 0 or 6% beef extract (BE). Half the rats fed each diet were subjected to compulsory exercise (CE) for 30 min every other day. After 4 weeks feeding, the blood was collected and various organs were dissected. The muscle fiber type of the soleus and extensor digitorum longus (EDL) muscles were evaluated by histochemical and electrophoretical analyses. Rats supplemented with BE showed a decrease in fat content in liver and abdomen and an increase in the activity of carnitine palmitoyl transferase II in liver. BE as well as exercise increased the relative weights of both soleus and EDL. BE alone and BE plus CE did not affect the distribution of muscle fiber types in soleus. BE without exercise decreased in type IIb of EDL from 54% to 44% with compensatory increase in type IIa from 41% to 49% and type I from 5% to 7% compared with the nonsupplemented, nonexercised control group. No synergetic effect on a fast to slow fiber conversion due to the combination of BE and CE was detected. Thus, BE supplement increased muscle mass and slow type fiber in EDL. The effects of BE supplement on muscle characteristics were similar to those of exercise. beef extract, fat metabolism, muscle fiber type, muscle mass, L-carnitine

IIa to IIb conversion and vise-versa isn't something that is usually disputed. To straight out say any sort of fiber conversion is something i disagree with, and the reason i posted my statement.

And i'm not saying some1 should be concerned with fiber conversion or fibers acting like different types. I started off this thread with saying that he probably shouldn't be so concerned about fast twitch versus slow twitch..... in sports training there is a correct way to train and a result to that training. And that his real question should be 'is increasing my leg strength carrying over to my sports' If he is not getting enough force output fast enough he need to go through a conversion phase to convert his 'powerlifting' style lifting to his sports. With RFD and plyometrics more specifically.

IIa to IIb conversion and vise-versa isn't something that is usually disputed. To straight out say any sort of fiber conversion is something i disagree with, and the reason i posted my statement.

And i'm not saying some1 should be concerned with fiber conversion or fibers acting like different types. I started off this thread with saying that he probably shouldn't be so concerned about fast twitch versus slow twitch..... in sports training there is a correct way to train and a result to that training. And that his real question should be 'is increasing my leg strength carrying over to my sports' If he is not getting enough force output fast enough he need to go through a conversion phase to convert his 'powerlifting' style lifting to his sports. With RFD and plyometrics more specifically.